Die bob



J. T. WILLMARTH.

Die for Bolt Machines.

No. 12,735. Patented April 17.- 1855.

To all whont ituntty mm *WI SWM QFFIQE- a @IQHNQT:wmLMARrrr; or NORTHBRIDGE; MASSACHUSETTS.

Inn Eon: BOLT-FORGING MAoHINEsf t rcase or LettersI'atentN .112,73 5, dated April 17, 1855.

Be it known that nJoHNlr wiLrMA m,

Diesgfof Machines for Making Bolts, of

I which the following M1111, clear, and ex c act description, reference being had to the ,jannexed drawings, making part of this which iymydiesxare operated. i will betreferred tohereafter.

specificatiominwhich a c Figure 8' isa section of. a; machine in Figs. 1 to 7 In the. machines heretofore contrived for the, purpose of manufacturing; bolts and other,similarparticles the ironhas in some casesbeen drawn down by subjecting it to successiveblows between flathorizontal surfaces, the bar being partially rotated between each -blow,by whichitis flattened out first in one direction, then in another, and thus gradually drawn out and diminishedln size. When iron is thus" worked it is liable to befcracked upon each side and'the fibers are broken, particularly in the center of the bar every time the upper die or hammer descends; each succeeding stroke increasing instead of repairing the defects. This detracts materiallyfrom the strength of the bolt or other article thus forged. In other cases when heavy iron has been forged a V a shaped anvil hasbeen employed, but this Q Would obviously not be applicable to the forging or drawing down of smallerarticles, which require to I be fin'ishedto an exact cylindrical form. I Such articles have been drawn down by operating upon them by a r series of semi-cylindrical dies in the opposite ginning with the largest and finishing with faces of a hammer and anvil, the iron being carried from one, die to the other, be-

the smallest. This methodjis liable to several gobjectionselst. The process. is slow and consequentlyexpensive; 2d. There is no method by which the exact amount of iron required for the shank of the bolt; can

be drawndown; 3d. A sprue is formed from the iron eachtime the dies close, and particularly each time the iron is moved to a smaller size die, which sprue is forced into thesurface ofthe iron when it is again turned half round, and a defective surface a which can never be. remedied by the after a hammering which it receives is the consequence. Such boltsare particularly inapplicable to the formation ofscrew bolts.

., My invention diifers from all these and consists in subjecting theiron to the acof Northbridge, in thejcounty; of Worcester and State. of Massachusetts, have invented certain new and. useful. Improvements in the tion of tapering conical dies, at the same time that it isdrawn gradually outofthem, by which means'it is more rapidly elongated than in either ofthe above cases, and the injurious consequences before mentioned are entirely avoided, the whole force of the blow, being expended in drawing out the iron in the direction of its length.

Toenable others skilled in the art to understandmy invention I will proceed to describe the manner in which I have carried.

itout. r

' 1 In Fig. Sis represented in section the machine in which the dies whichform the. 7

subject of; mypresent invention are operated. Thls machine is substantially similar to that describedin Letters Patent granted to me on the 16th January 1'855for improved dies for making bolts and I will briefly refer to its principal parts and the manner in which it operates.

B, B, is the bed piece or foundation which holds the lower dies 72, the upper dies 6 being secured to the side pieces D,

thesegudgeons so as to bring the dies in the slde pieces alternately into operation upon those in the bed pieces B, B as followsK is the main driving shaft which revolves in standards rising from the ends of the machine, and to which the driving pulley and the fly wheel N are secured-L, are eccentrics secured to the shaft K and running in the straps M. These straps are grooved so as to slide freely up and down in the side posts E, and thus as the shaft K revolves, the upper die frame is vibrated upon its gudgeons. The dies 6 b which form the subject of my present invention are arranged in pairs as seen in the various figures. Figure l is a front view of them. Figs. 2 and 3 are vertical sections taken longitudinally through the cavity between them upon the line a, 2, of Fig. 1. Fig. 4 a vertical section transverse to the cavity between them upon the line W, W, of Fig. 3. Fig. 5 is a plan of one of them.

From an inspection of these figures it will be seen that when these dies are closed together the space between them (r) for a short distance from their front face is very nearly cylindrical, and that it then flares out so as to form a tapering conical cavity, the size of the shorter diameter of the portion 7, of this cavity corresponding to that of the finished bolt. This flattened or oval form is given to the dies in preference to an eXact cylindrical form, that the edges of the dies when the two come together may not cut the iron, and throw out a sprue at the sides, the conical portion of the die is also flattened in a similar manner, and for the same purpose. The iron which is to be drawn down by these dies has already been operated upon and prepared by the dies for which Letters Patent were granted to me on the 16 January 1855 as before mentioned; these dies are seen in section in Fig. 7 of the accompanying drawings, but need not be further described as they form no part of my present invention. The iron as it leaves these dies is of the form represented in Fig. 6; in this form it is submitted to the action of the dies 6, I), being inserted between them as seen in Fig. 2, the portion 25 being made to enter the cavity 9; it is then continually rotated and gradually withdrawn until as seen in Fig. 3 the shank of the bolt is formed, the iron being brought to its ultimate size at a single operation. The bolt may be ultimately smoothed by the cylindrical dies y, or pointed in the dies as if required; these dies are made perfectly cylindrical and of the exact size of the finished bolt.

It is evident that when thus operated upon by tapering, conical dies the iron is confined at the sides at the instant it receives the blow, and is drawn out lengthwise, and is not continually flattened out in opposite directions as is the case when other forms of dies are used.

The dies above described are equally well adapted to the purpose of drawing down any iron which requires to be reduced in size, I do not therefore limit myself to their use in the manufacture of bolts alone, but

intend to employ them whenever in the manufacture of iron they may be found useful.

What I claim as my invention and desire to secure by Letters Patent are The tapering, conical dies 6 b constructed and operating in the manner substantially as herein described for the purpose set forth.

JOHN T. WILLMARTH.

WVitnesses:

SAM. COOPER, EBEN HoYT, Jr. 

